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931.
Xu L Chen X Chen J Zhang F He C Du K Wang Y 《Environmental science and pollution research international》2012,19(5):1443-1453
Background
PM10 aerosol samples were simultaneously collected at two urban and one urban background sites in Fuzhou city during two sampling campaigns in summer and winter. PM10 mass concentrations and chemical compositions were determined.Methods
Water-soluble inorganic ions (Cl?, NO 3 ? , SO 4 2? , NH 4 + , K+, Na+, Ca2+, and Mg2+), carbonaceous species (elemental carbon and organic carbon), and elements (Al, Si, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, and Pb) were detected using ion chromatography, thermal/optical reflectance, and proton-induced X-ray emission methods, respectively.Results
PM10 mass concentrations, as well as most of the chemical components, were significantly increased from urban background to urban sites, which were due to enhanced anthropogenic activities in urban areas. Elements, carbonaceous species, and most of the ions were more uniformly distributed at different types of sites in winter, whereas secondary ion SO 4 2? , NO 3 ? , and NH 4 + showed more evident urban-background contrast in this season. The chemical mass closure indicated that mineral dust, organic matters, and sulfate were the most abundant components in PM10. The sum of individually measured components accounted for 86.9?C97.7% of the total measured PM10 concentration, and the discrepancy was larger in urban area than in urban background area.Conclusion
According to the principal component analysis?Cmultivariate linear regression model, mineral dust, secondary inorganic ions, sea salt, and motor vehicle were mainly responsible for the PM10 particles in Fuzhou atmosphere, and contributed 19.9%, 53.3%, 21.3%, and 5.5% of PM10, respectively. 相似文献932.
混合硫酸盐还原菌代谢过程的影响因素 总被引:1,自引:1,他引:0
采用间歇实验,研究不同初始pH、Fe2+投加量、COD/SO24-及NO3-/SO24-比值等因素对SRB还原硫酸盐效果与速率的影响。实验结果表明:中性条件下(pH=7),硫酸盐的去除效果最佳,去除率达到84.66%,还原速率为15.07 mg/(L.h),在初始pH为4~9的范围内,体系具有较好的缓冲能力;当COD/SO24-比值为3时,反应209 h,硫酸盐去除率为85.33%,还原速率为8.16 mg/(L.h),随着反应的进行,体系的pH趋于中性;当溶液中有亚铁离子存在,且浓度为0~200 mg/L时可促进硫酸盐还原菌的生长,提高其对硫酸盐的去除率;NO3-对硫酸盐的还原有明显的抑制作用。 相似文献
933.
934.
强制循环厌氧反应器处理中低浓度废水 总被引:1,自引:0,他引:1
为解决内循环厌氧反应器在对低浓度有机废水处理时,因产气量不足、内循环量小而不能正常运行的问题,提出了强制循环反应器的概念,给出了设计方法。以低浓度、碱性印染工业废水为研究对象,进行了强制循环厌氧反应器的启动与运行的研究,得出了该反应器的最佳HRT和最佳外加循环量。结果表明:在高硫、低性状絮状厌氧泥为接种泥情况下,最佳外循环流量1 m3/h,最佳HRT为7 h时,FCR出水的T-COD和S-COD去除率分别为53.6%和58%。 相似文献
935.
通过自组装技术在低温液相反应体系中制备出大尺寸纳米二氧化钛及其掺碘薄膜。使用XRD、TEM、荧光发射光谱仪、激光拉曼光谱仪等手段对样品进行表征,发现掺I^5+后的二氧化钛薄膜在可见光区也表现出明显的响应,而且合成的I^5+/TiO2纳米薄膜在TEMggNT其晶型显示为金红石型,并且碘掺杂后样品的拉曼光谱强度减弱,峰位蓝移且宽化。掺杂I^5+原溶液浓度为2mmol/L时,其可见光下光催化效果最优,5h后降解率可达到95%,较未掺杂的TiO2纳米薄膜提高了40%,I^5+掺杂明显提高了TiO2对甲基橙溶液的光催化降解效率。 相似文献
936.
The potential of using mollusk shell powder in aragonite (razor clam shells, RCS) and calcite phase (oyster shells, OS) to remove Pb2+, Cd2+ and Zn2+ from contaminated water was investigated. Both biogenic sorbents displayed very high sorption capacities for the three metals except for Cd on OS. XRD, SEM and XPS results demonstrated that surface precipitation leading to crystal growth took place during sorption. Calcite OS displayed a remarkably higher sorption capacity to Pb than aragonite RCS, while the opposite was observed for Cd. However, both sorbents displayed similar sorption capacities to Zn. These could be due to the different extent of matching in crystal lattice between the metal bearing precipitate and the substrates. The initial pH of the solution, sorbent’s dosage and grain size affected the removal efficiency of the heavy meals significantly, while the organic matter in mollusk shells affected the removal efficiency to a lesser extent. 相似文献
937.
Du LN Zhao M Li G Zhao XP Zhao YH 《Environmental science and pollution research international》2011,19(7):2898-2907
Purpose
Malachite Green (MG) is used for a variety of applications but is also known to be carcinogenic and mutagenic. In this study, a novel Micrococcus sp. (strain BD15) was observed to efficiently decolorize MG. The purposes of this study were to explore the optimal conditions for decolorization and to evaluate the potential use of this strain for MG decolorization.Methods
Optical microscope and UV?Cvisible analyses were carried out to determine whether the decolorization was due to biosorption or biodegradation. A Plackett?CBurman design was employed to investigate the effect of various parameters on decolorization, and response surface methodology was then used to explore the optimal decolorization conditions. Kinetics analysis and antimicrobial activity tests were also performed.Results
The results indicated that the decolorization by the strain was mainly due to biodegradation. Concentrations of MG, urea, and yeast extract and inoculum size had significantly positive effects on MG decolorization, while concentrations of CuCl2 and MgCl2, and temperature had significantly negative effects. The interaction between different parameters could significantly affect decolorization, and the optimal conditions for decolorization were 1.0 g/L urea, 0.9 g/L yeast extract, 100 mg/L MG, 0.1 g/L inoculums (dry weight), and incubation at 25.2°C. Under the optimal conditions, 96.9% of MG was removed by the strain within 1 h, which represents highly efficient microbial decolorization. Moreover, the kinetic data for decolorization fit a second-order model well, and the strain showed a good MG detoxification capability.Conclusion
Based on the results of this study, we propose Micrococcus sp. strain BD15 as an excellent candidate strain for MG removal from wastewater. 相似文献938.
Bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers in wild frogs 总被引:1,自引:0,他引:1
Liu PY Du GD Zhao YX Mu YS Zhang AQ Qin ZF Zhang XY Yan SS Li Y Wei RG Qin XF Yang YJ 《Chemosphere》2011,84(7):972-978
To investigate bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers (PBDEs) in amphibians, we collected adult frogs (Rana limnocharis) from a rice field in an e-waste recycling site in China. We found that ∑PBDEs in the whole frogs and various tissues (brain, liver, testis and egg) ranged from 17.10 to 141.11 ng g−1 wet weight. Various tissues exhibited a similar PBDE congener profile, which was characterized by intermediate brominated congeners (BDE-99 and BDE-153) as the largest contributors, with less lower brominated congeners (BDE-28 and BDE-47) and higher brominated congeners (BDE-209). The maternal transfer capacity of PBDEs declined with the increase in bromine numbers of PBDE congeners. We suggest that the bromine atom number (the molecular size, to some degree) might be a determining factor for the maternal transport of a PBDE congener rather than Kow (Octanol-Water partition coefficient), which expresses a compound’s lipophilicity. ∑PBDEs concentrations in frogs decreased over time during a depuration period of 54 days when these wild frogs were brought to the lab from the e-waste recycling site. The half-life of ∑PBDEs was 35 days, with about 14 days for BDE-47, and 36 and 81 days for BDE-99 and BDE-153, respectively. The data shows that the elimination of PBDEs has no essential difference from aquatic and terrestrial species. 相似文献
939.
940.